Obtains the value of a field

Description

Usage

Arguments

o

Class name or object (Java reference) whose field is to be
accessed. Static fields are supported both by specifying the class
name or using an instance.

sig

signature (JNI type) of the field. If set to NULL
rJava attempts to determine the signature using reflection. For
efficiency it is recommended to specify the signature, because
the reflection lookup is quite expensive.

name

name of the field to access

true.class

by default the class of the resulting object matches
the siganture of the field. Setting this flag to TRUE causes
.jfield to use true class name of the resulting object
instead. (this flag has no effect on scalar fields)

convert

when set to TRUE all references are converted to
native types (where possible). Otherwise Java references are
returned directly.

value

value to assign into the field. The field signature is
determined from the value in the same way that parameter signatures
are determined in .jcall - be sure to cast the value
as necessary, no automatic conversion is done.

Details

The detection of a field signature in .jfield using reflection
is considerably expensive (more than 3 additional method calls have to
be performed), therefore it is recommended for time-critical code to
specify the field signature beforehand.

NOTE: The sequence of arguments in .jfield has been changed
since rJava 0.5 to be more consistent and match the sequence in
.jcall. Also .jsimplify is no longer needed as primitive
types are obtained directly.